diff options
| -rw-r--r-- | src/drivers/i2c/tpm/tis.c | 29 |
1 files changed, 26 insertions, 3 deletions
diff --git a/src/drivers/i2c/tpm/tis.c b/src/drivers/i2c/tpm/tis.c index 696634d9d7..d9a7651008 100644 --- a/src/drivers/i2c/tpm/tis.c +++ b/src/drivers/i2c/tpm/tis.c @@ -29,6 +29,7 @@ #include <device/i2c.h> #include <tpm.h> #include "tpm.h" +#include <timer.h> #include <console/console.h> @@ -37,6 +38,7 @@ struct tpm_chip g_chip; #define TPM_CMD_COUNT_BYTE 2 #define TPM_CMD_ORDINAL_BYTE 6 +#define TPM_VALID_STATUS (1 << 7) int tis_open(void) { @@ -74,12 +76,33 @@ int tis_init(void) { int bus = CONFIG_DRIVER_TPM_I2C_BUS; int chip = CONFIG_DRIVER_TPM_I2C_ADDR; + struct stopwatch sw; + uint8_t buf = 0; + int ret; + long sw_run_duration = 750; /* - * Probe TPM twice; the first probing might fail because TPM is asleep, - * and the probing can wake up TPM. + * Probe TPM. Check if the TPM_ACCESS register's ValidSts bit is set(1) + * If the bit remains clear(0) then claim that init has failed. */ - if (i2c_writeb(bus, chip, 0, 0) && i2c_writeb(bus, chip, 0, 0)) + stopwatch_init_msecs_expire(&sw, sw_run_duration); + do { + ret = i2c_readb(bus, chip, 0, &buf); + if (!ret && (buf & TPM_VALID_STATUS)) { + sw_run_duration = stopwatch_duration_msecs(&sw); + break; + } + } while (!stopwatch_expired(&sw)); + + printk(BIOS_INFO, + "%s: ValidSts bit %s(%d) in TPM_ACCESS register after %ld ms\n", + __func__, (buf & TPM_VALID_STATUS) ? "set" : "clear", + (buf & TPM_VALID_STATUS) >> 7, sw_run_duration); + + /* + * Claim failure if the ValidSts (bit 7) is clear. + */ + if (!(buf & TPM_VALID_STATUS)) return -1; return 0; |